Does the Split Stop It? — TechKnowSurge

About this interactive

A local area network is a set of devices joined by switches into one broadcast domain. That closeness is the weakness: an ARP request or any other broadcast reaches every device, a MAC address is easy to fake, and there is nowhere to put a layer 3 firewall or access list between two devices on the same switch. Segmentation breaks one network into several. Northwind's Sales, Operations and Guest each become a network of their own, with a firewall in front of them. Broadcasts and spoofing stay on their own side, and anything that crosses from one segment to another has to pass the firewall, which lets through only what each team needs. A worm on a guest laptop, or a salesperson browsing the Operations server, stops there. What segmentation does not do is protect devices from each other inside one segment. Two Sales PCs on the same switch still talk freely, a rogue device can still spoof its neighbours, and a stolen Sales login still opens the Sales share. The split limits how far a problem spreads; inside each segment you still need other controls.

What you'll learn

Predict whether splitting one flat LAN into separate networks with a firewall between them stops an event, or whether the event can still happen inside one segment
Explain why: broadcasts, MAC spoofing and device-to-device traffic stay inside one layer 2 network, while traffic between segments has to cross a layer 3 boundary that a firewall controls

Aligned to

CompTIA Security+

2.5 Explain the purpose of mitigation techniques used to secure the enterprise.

3.2 Given a scenario, apply security principles to secure enterprise infrastructure.

3.1 Compare and contrast security implications of different architecture models.

Key terms

Network Segmentation: The practice of dividing a network into smaller segments to improve performance and limit the spread of security threats.
Broadcast Domain: A network segment in which a broadcast sent by one device is received by all other devices within that segment; routers define the boundaries of broadcast domains by not forwarding broadcast traffic.
Local Area Network: A network that connects devices within a limited geographic area such as a home, office floor, or building, where all devices share the same broadcast domain and communicate at high speeds with low latency. A router defines the boundary of a LAN by separating it from other networks.
Guest Network: An isolated network segment provided to visitors that is separated from the organization's internal network to prevent unauthorized access to internal resources.
Firewall: A network security device that monitors and controls incoming and outgoing traffic based on predefined security rules.
Layer 3: The Network layer of the OSI model, responsible for logical addressing and routing packets between networks.

Topics

Network Segmentation Broadcast Domain Guest Network Firewall Interactive Streak Sort

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